rav -
Welcome to EM! Here are some good threads on the subject (maybe you've already read them) :
Where to buy vortex generator fins?
Tested: vortex generators (AirTabs) on a Toyota Corolla
As other people have suggested, you could come up with your own. If you can't justify the cash outlay for a set of airtabs, you could buy just one airtab and use it as a mold to make your own.
CarloSW2